Wednesday, 11 January 2012
The current book I’m reading in the morning after breakfast is Roberto Casati’s The Shadow Club, recommended naturally - it’s a study of the cultural and scientific history of shadows. I got this morning to the section What do we think we know about the moon?, and I quote the first sentences: ‘The students were reminded that a lunar eclipse is produced when the earth casts its shadow on the moon. Then they were asked whether lunar eclipses are more frequent when the moon is full or when it’s in its first or last quarter – when there’s only a crescent moon. The majority of students believed eclipses are more frequent with crescent moons.’
I was not concentrating during the first sentence, but the move into italics brought me up sharp. Quickly doing the mental picture in my head I calculated that a lunar eclipse would happen when the moon is new, surely – an eclipse caused by the moon, its shadow falling on the earth. Completely wrong – a lunar eclipse happens when the earth is between the sun and the moon. The ‘-ar’ suffix in an adjective does not mean ‘caused by’, but ‘pertaining to’. The derivation of the ‘–ar’ suffix is the Latin –arem, which comes into English as ‘-ar’ or ‘-al’, as in ‘scholar’ or ‘legal’, with the meaning ‘pertaining to or belonging to’. Thus, a lunar eclipse is one which pertains to the moon, and ‘belongs to’ the moon, and certainly happens on the moon. The process is reversed for a solar eclipse, which happens on the surface of the earth, when the moon moves between the sun and the earth. Only the egoism of the human gaze sees a solar eclipse as one which pertains to the sun rather than the earth.